It's not really a replacement, some recipes suggest it has a flavour like leeks but I can't say that I have found that.I often use it to give an extra dimension to some dishes like you would with umami paste etc.start off sparingly, say, a quarter of a tsp in a large pan of soup and work up (or down) from there.I would use it at the beginning of cooking, when the oil is hot enough to make it sizzle, just before putting in the other ingredients. I love it but it's something that could overpower if you use too much - err on the subtle side.

i think asafoetida is the closest that you can get now to silphium, a plant made extinct in roman times due to the fact that they couldn't get enough of it for their cooking. it is said that the last surviving 'bulb' was presented to nero. there have been claims that it has been seen near it's ancient natural habitat in a small area of north africa but that may be wishful thinking.asafoetida is said to be a poorer cousin but at least it's easily available.

Used it again yesterday. Didn't notice the smell, until after I'd gone out to get the boys from school, then noticed the house smelled (smelt?) of it so much! Made some low fodmap (also vegetarian, gluten free, nut free and oral allergy syndrome-safe) burgers with it, which didn't really taste of much Think the spices got a bit lost in them. But with all the cheese, roast tomatoes, roast peppers and buttery cooked chard I put in to the bun with them (well actually two crusts of a GF loaf!), the whole meal was rather tastey!